A crowd of several hundred people has gathered outside Ports of Auckland today to protest at port expansion plans.

The protest, organised by Stop Stealing Our Harbour, will march from Quay St to the Viaduct Events Centre.

On Thursday, Auckland Mayor Len Brown used his casting vote for a compromise over the port company's wharf extension dispute.

The compromise followed a last-minute offer by Ports of Auckland to stop extending the western end of Bledisloe Wharf by 92m into Waitemata Harbour, pending completion of a port future study by April 30 next year.

Although a council staff report said that would address a number of community concerns, especially around sight lines from Queens Wharf, it means work can continue on a 98m extension from the wharf's eastern end.

Councillors opposed to compromise accused the port company of arrogance in taking four weeks to respond to a unanimous resolution of the city development committee, calling for it to stop all work pending the strategic study.

Protest group Stop Stealing Our Harbour said allowing the longer wharf extension to continue in defiance of public opinion was "nothing short of a one-fingered salute to the people of Auckland".

An earlier protest against the wharf extensions on March 22 attracted about 2000 people to Queens Wharf and a flotilla of about 300 boats to the harbour in support

Speakers at the events centre include councillors Chris Darby and Chris Fletcher, Labour MP Jacinda Ardern, Rangimarie Hunia of Ngati Whatua, businessman Tenby Powell and yachting commentator Peter Montgomery.